Coregonids....?

or whitefish... I have found a book that was given to me by a work colleague
10 years ago. It is the Collins encyclopedia of fishing in the British isles.
Edited by Michael Prichard. The illustrations of fish are stunning in detail and I cannot put it down........ 1st published 1977.
Anyway, page 225 I found wonderful pics of these fish.
Powan ,Shelly, gwynaid, Vendace ,Pollan and Houting.
I always vaguely knew that these fish were rare but still found in the north west, Ireland, and lake bala in Wales.
Are they still there ?

I heard that many of these endemic white fish were on the way towards extinction due to introduced species like ruffe, roach and perch. Along with the eutrophication of their habitat. Houting is the extinct migratory whitefish- north sea houting.

To my knowledge all forms are still present, but are under increased threat. It'd be a great shame to lose these unique species.